The purpose of this study is to compare two accepted methods of pain control in knee arthroplasty surgery.The first method combines the periarticular injection of ropivacaine with continuous blockade of the femoral nerve.The second method uses periarticular infiltration of ropivacaine in combination with an bolus of ropivacaine into an intraarticular catheter placed intraoperatively followed by a continuous intraarticular infusion of ropivacaine. All patient will also receive a sustained-release oral opioid and oral rescue opioids determined by pain severity using the Visual Analog Scale (VAS)